I don't know if you can find it in pgh, but we have a brewery in NEPA called the Lion Brewery. They're stuff is good, but comes in around $20 a case.
Molson Ice could fit your bill. I was paying $6 for a 6 pack, so by the case it should be around $15. A little light on taste though.
Yengleng isn't bad and can be had close to your price range.
Generally, I have a simple rule. I'm not going to buy beer that doesn't taste good just because money is tight. So, I'll either end up paying $25+ for a case or just not buying any...